Resilient Anchor

ABSTRACT

Methods and apparatus for radially expanding and plastically deforming an expandable tubular member using an expansion device for radially expanding and plastically deforming the expandable tubular member, an actuator coupled to the expansion device, and an anchor coupled to the actuator. The anchor includes a resilient member that is selectively deformable between a first position wherein the resilient member does not engage the expandable tubular member and a second position wherein the resilient member engages the expandable tubular member so as to releasably couple the anchor to the expandable tubular member.

BACKGROUND

In the oil and gas industry, expandable tubing is often used for casing, liners and the like. To create a casing, for example, a tubular member is installed in a wellbore and subsequently expanded by displacing an expansion cone through the tubular member. The expansion cone may be pushed or pulled using mechanical means, such as by a support tubular coupled thereto, or driven by hydraulic pressure. As the expansion cone is displaced axially within the tubular member, the expansion cone imparts radial force to the inner surface of the tubular member. In response to the radial force, the tubular member plastically deforms, thereby permanently increasing both its inner and outer diameters. In other words, the tubular member expands radially. Expandable tubulars may also be used to repair, seal, or remediate existing casing that has been perforated, parted, corroded, or otherwise damaged since installation.

SUMMARY OF INVENTION

In one aspect, the present disclosure relates to methods and apparatus for radially expanding and plastically deforming an expandable tubular member using an expansion device, an actuator coupled to the expansion device, and an anchor coupled to the actuator. The anchor includes a resilient member that is selectively deformable between a first position wherein the resilient member does not engage the expandable tubular member and a second position wherein the resilient member engages the expandable tubular member so as to releasably couple the anchor to the expandable tubular member.

Other aspects and advantages of the invention will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary cross-sectional illustration of an apparatus for installing an expandable tubular member within a preexisting structure.

FIG. 2 is a fragmentary cross-sectional illustration of the apparatus of FIG. 1 after displacing the expansion device within the expandable tubular member.

FIG. 3 is a fragmentary cross-sectional illustration of the apparatus of FIG. 2 after displacing the actuator and anchor relative to the expansion device and the expandable tubular member.

FIG. 4 is a fragmentary cross-sectional illustration of the apparatus of FIG. 3 after displacing the expansion device within the expandable tubular member.

FIG. 5A-5B are partial schematic illustrations of an anchor activated by axial compression in accordance with one embodiment.

FIG. 6A-6B are partial schematic illustrations of an anchor activated by radial expansion in accordance with another embodiment.

FIG. 7 is a cross-section of an anchor in accordance with one embodiment.

FIGS. 8A-8C are detailed isometric views of a resilient member for use with the anchor shown in FIG. 7 in accordance with one embodiment.

FIG. 9 is a fragmentary cross-sectional illustration of an apparatus for anchoring a workstring to a tubular member.

FIG. 10 is a fragmentary cross-sectional illustration of the apparatus of FIG. 9 with the workstring anchored to the tubular member.

DETAILED DESCRIPTION

The present disclosure relates to apparatus and methods for anchoring a workstring within a tubular member such that a process can be performed on the tubular member. In some embodiments, the anchored workstring is used to move the tubular member within a wellbore. In other embodiments, the anchored workstring includes an expansion apparatus operable to radially expand the tubular member within a wellbore.

Referring to FIG. 1, an embodiment of an expansion apparatus 10 for radially expanding and plastically deforming a tubular member 12 includes a tubular support member 14 that is coupled to an end of an anchor 16 for controllably engaging the tubular member via resilient member 26. Another end of the anchor 16 is coupled to a tubular support member 18 that is coupled to an end of an actuator 20. Another end of the actuator 20 is coupled to a tubular support member 22 that is coupled to an end of an expansion device 24 for radially expanding and plastically deforming the tubular member 12. The anchor 16, the tubular support member 18, the actuator 20, and the tubular support member 22 are positioned within the tubular member 12.

In one embodiment, the expansion apparatus 10 is positioned within a preexisting structure 30 such as, for example, a wellbore that traverses a subterranean formation 32. Once tubular member 12 and expansion apparatus 10 are disposed at a desired location within structure 30, anchor 16 is activated. The activation of anchor 16 causes resilient member 26 to deform and engage tubular member 12 so as to releasably couple anchor 16 to tubular member 12. As a result, the axial position of anchor 16 is fixed relative to tubular member 12, as shown in FIG. 2. The activation of anchor 16 is further detailed below in reference to FIGS. 5A-5B and 6A-6B. Once anchor 16 is releasably coupled to tubular member 12, actuator 20 can be activated to axially displace the expansion device 24 relative to tubular member 12. The axial displacement of expansion device 24 radially expands and plastically deforms a portion of the tubular member 12.

Once actuator 20 has displaced expansion device 24, as illustrated in FIG. 3, the anchor 16 is then deactivated, which disengages resilient member 26 from the tubular member 12. With anchor 16 released, the tubular support member 14, the anchor 16, the tubular support member 18, and the actuator 20 can be displaced axially relative to the expansion device 24. The axial displacement of anchor 16 and actuator 20 may be effectuated by pulling support member 14 upward or through a reversal of the activation of actuator 20.

As illustrated in FIG. 4, the anchor 16 is again releasably coupled to tubular member 12 by deforming resilient member 26 into engagement with tubular member 12. Actuator 20 is activated to further axially displace expansion device 24 relative to tubular member 12. As expansion device 24 is displaced by the actuator 20, another portion of tubular member 12 is radially expanded and plastically deformed. The operations of FIGS. 3 and 4 can then be repeated until the desired length of the tubular member 12 is radially expanded and plastically deformed. The process of anchoring and releasing may be repeated many times to allow repeated expansion steps. The strains imposed on the resilient members may be limited to avoid any permanent deformation of resilient member 26 and allow virtually unlimited actuation of the anchor 26.

For example, in the embodiments shown in FIGS. 1-4, the actuator 20 may be configured for a stroke length of 3 feet and 3000 feet of tubular member 12 may be expanded. The anchor 16 could be actuated to anchor the support member 14, the actuator 20 then stroked 3 feet to expand a portion of tubular member 12 with expansion device 24, followed by release of the anchor 16. Pulling up on the support member 14 resets the actuator 20 and allows a repeat of the anchoring and expansion in the 3 foot intervals until the tubular member 12 is expanded.

It is understood that expansion apparatus 10 is only one embodiment of a system utilizing an anchor, actuator, and expansion device and other such systems may be contemplated or are known in the art. For example, the expansion device may be a solid mandrel having a fixed outer diameter, an adjustable or collapsible mandrel with a variable outer diameter, a roller-type expansion device, or any other device used to expand a tubular. Still further, although illustrated in FIG. 1 as having all initial position external to the expandable tubular member and configured for upward expansion, in certain embodiments, the expansion device may have an initial position within the tubular and/or be configured for downward expansion. Expansion apparatus 10 may also utilize any actuator that provides sufficient force to axially displace the expansion device through the expandable tubular. The actuator may be driven by hydraulic pressure, mechanical forces, electrical power, or any other suitable power source.

FIGS. 5A and 5B schematically illustrate one embodiment of an anchor 112 comprising a resilient member 126 that is deformed by the application of an axial force on the resilient member. Resilient member 126 is a substantially cylindrical body disposed about a support member 134. Resilient member 126 is axially constrained on one end by flange 128. Piston 130 is disposed adjacent to the other end of resilient member 126. When anchor 112 is activated, piston 130 moves toward flange 128 and axially compresses resilient member 126.

The axial compression of resilient member 126 increases the outside diameter of the resilient member according to the material properties, such as Poisson's ratio, of the resilient material. For example, a urethane formulated for a downhole environment may have a Poisson's ratio of about 0.50. As a result of the axial compression, the outside of the resilient member 126 comes into contact with, and develops a normal force on, the inner diameter of the tubular member 132. Further axial compression of the resilient member 126 adds to the normal force, which provides the anchoring force for the anchor 112. The anchoring force is approximately the product of the normal force applied to the inner diameter of the tubular member 132 and the coefficient of friction between the tubular member 132 and the resilient member 126.

In certain embodiments, resilient member 126 may exert a force on tubular member 132 that is sufficient to cause deformation of the tubular member 132. This localized deformation of tubular member 132 may further increase the anchoring force generated by resilient member 126 as the resilient member would have to be sheared or compressed in order to exit the area that has been deformed.

FIGS. 6A and 6B schematically illustrate another embodiment of an anchor 212 comprising a resilient member 226 that is deformed by radially expanding the resilient member using a tapered mandrel 228. Resilient member 226 is a substantially cylindrical body disposed about a support member 230. Tapered mandrel 228 is also disposed about support member 230 and is axially moveable relative thereto. Resilient member 226 is axially constrained on one end by flange 232. When anchor 212 is activated, tapered mandrel 228 is moved toward flange 232.

The axial movement of tapered mandrel 228 forces resilient member 226 to radially expand outward over the tapered mandrel and into contact with tubular member 234. As a result of the radial expansion, the outside of the resilient member 226 comes into contact with, and develops a normal force on the inner diameter of the tubular member 234. Further radial expansion of the resilient member 226 adds to the normal force, which provides the anchoring force for the anchor 212. The anchoring force is approximately the product of the normal force applied to the inner diameter of the tubular member 234 and the coefficient of friction between the tubular member 234 and the resilient member 226.

In certain embodiments, resilient member 226 may exert a force on tubular member 234 that is sufficient to cause deformation of the tubular member. This localized deformation of tubular member 234 may further increase the anchoring force generated by resilient member 226 as the resilient member would have to be sheared or compressed in order to exit the area that has been deformed.

In FIG. 7, an anchor in accordance with one embodiment is shown. The anchor uses resilient members 702 a and 702 b disposed around an anchor body 701 to selectively engage the inside of tubular member 12 to anchor support member 14 with respect to tubular member 12. Engagement of the resilient members 702 a and 702 b is controlled by axially compressing the resilient members 702 a and 702 b, which increases the outside diameter of the resilient members 702 a and 702 b according to the material properties of the particular material, such as Modulus of Elasticity, and Poisson's ratio. As a result of the axial compression, the outside of the resilient members 702 a and 702 b come into contact with the inside of the tubular member 12, which develops a normal force on the inner diameter of the tubular member 12. Further axial stress on the resilient members 702 a and 702 b adds to the normal force, which provides the anchoring force for the anchor. The anchoring force is approximately the product of the normal force applied to the inner diameter of the tubular member 12 and the coefficient of friction between the tubular member 12 and the resilient members 702 a and 702 b.

The form and function of the anchor shown in FIG. 7 will now be described in greater detail. Those having ordinary skill in the art will appreciate that many modifications may be made to the embodiment shown in FIG. 7 in accordance with the teachings herein. At one end, the anchor body 701 includes a connection, such as a threaded connection, to the support member 14. The opposing end of the anchor body 701 is connected to other components of the expansion apparatus, such as an actuator (not shown). The anchor includes two resilient members 702 a and 702 b that are generally cylindrical in shape and disposed on the anchor body 701. In the relaxed or undocked state, as shown in FIG. 7, the outside diameter of the resilient members 702 a and 702 b is less than the inside diameter of the tubular member 12 to allow movement of the expansion apparatus.

The resilient members 702 a and 702 b are axially trapped by a top compression flange 720 and a bottom compression flange 721, respectively. The resilient members 702 a and 702 b are separated by a center wedge 715. The surfaces of center wedge 715 and compression flanges 720 and 721 that contact the ends of resilient members 702 a and 702 b are curved, which helps to force the resilient members radially outward as they are axially compressed by the compression flanges. The resilient members 702 a and 702 b may further include reinforcement members, such as anti-extrusion inserts 703 a-d to reduce or eliminate axial extrusion. The anti-extrusion inserts 703 a-d are formed from less flexible material, such as Teflon® or Nylon®, and may be separate or integrally bonded with the resilient members 702 a and 702 b.

In the embodiment shown in FIG. 7, the top compression flange 720 and the bottom compression flange 721 act as pressure-driven pistons to axially compress and radially expand the resilient members 702 a and 702 b. The respective piston areas are defined by the inside diameters of an upper retainer 701 and a lower retainer 711 and the outside diameter of a mandrel portion 705 of the anchor body 701. O-rings or any other sealing arrangement may be used to seal between the respective inside and outside diameters of the top compression flange 720, the bottom compression flange 721, the mandrel portion 705 of the anchor body 701, the upper retainer 701, and the lower retainer 711. To anchor the support member 14, pressure from the inside of the anchor is transmitted through ports 730 a to actuate the top compression flange 720 and through ports 730 b to actuate the bottom compression flange 721. The pressure differential between the inside of the anchor and the annulus between the tubular member 12 and the anchor body 701 axially moves the top compression flange 720 and the bottom compression flange 721 towards each other, thereby axially compressing the resilient members 702 a and 702 b. The resulting radial strain brings the outside of the resilient members 702 a and 702 b into contact with the inside of the tubular member 12. Releasing pressure causes the resilient members 702 a and 702 b to radially contract and axially extend to return to the relaxed state and release the anchor, thereby allowing movement of the support member 14 relative to the tubular member 12.

Although a pressure actuated embodiment is shown in FIG. 7, those having ordinary skill in the art will appreciate that the anchor could be actuated using other means, such as an electric motor with a linear actuator. Furthermore, the present disclosure is not limited to any number of resilient members. In some embodiments, a single resilient member may provide sufficient anchoring force. Those having ordinary skill in the art will appreciate that the amount of anchoring force needed will depend on many factors, such as the material strength, diameter, and thickness of the tubular member being expanded.

FIGS. 8A-8C illustrate a resilient member 802 that may be used with the anchor shown in FIG. 7. In this embodiment, the resilient member 802 is generally cylindrical, but includes azimuthally arranged cuts or grooves 801 on the exterior to relieve hoop stress in the resilient member 802. Grooves 801 also allow fluid bypass, which may be desirable for pressure equalization or fluid transfer across resilient member 802. Extrusion inserts 803 are at opposing ends of each section of the resilient member 802, Because of the grooves 801, the extrusion inserts 803 will experience less strain during actuation of the resilient member 802, which prevents or minimizes the risk of plastic deformation of the extrusion inserts 803. Extrusion inserts 803 are one example of a reinforcement member that may be used to improve the performance of resilient member 802. Other reinforcement members may include wire mesh, fibers, balls, and/or other materials combined with the resilient material.

Referring now to FIGS. 9 and 10, workstring 310 comprises anchor device 316 that is coupled to support member 314. Workstring 310 is disposed within tubular member 312 that may be at the surface or may be disposed within wellbore 330. Anchor device 316 includes resilient member 326 that is operable to engage tubular member 312. Workstring 310 is disposed within tubular member 312 with resilient member 326 in a first position, as shown in FIG. 9, where the resilient member does not contact the tubular member. Once workstring 310 is positioned within tubular member 312, resilient member 326 is selectively deformed to a second position, as shown in FIG. 10, by the activation of anchor device 316.

The activation of anchor device 316 couples workstring 310 to tubular member 316. Workstring 310 can then be used to move tubular member 312 within wellbore 330. For example, workstring 310 may be installed within tubular member 312 at the surface and then be used to lower the tubular member into wellbore 330, such as during casing running or liner drilling operations. Workstring 310 may also be installed within a tubular member 312 that is already in wellbore 330 to enable the tubular member to be removed from the wellbore, such as during fishing operations. As described above in relation to FIGS. 1 and 2, workstring 310 may also be used to engage tubular member 312 to perform a radial expansion operation. In certain embodiments, anchor device 316 may be operable to transmit torque from workstring 310 to tubular member 316, so that the tubular member can be rotated.

Anchors utilizing resilient members as disclosed herein provide an anchor that is less sensitive than other anchoring systems to variations in the inside diameter of the tubular member being expanded. Eccentricity and surface flaws are forgiven by the resilient members pressed against the inside of the tubular member because the resilient members conform to whatever surface they are pressed against. Additionally, the anchors can be configured to anchor within a range of internal diameters to take advantage of the range of radial strain tolerated by the resilient members. Unlike slips or pawls used in other anchoring systems, anchors utilizing resilient members do not gouge or otherwise damage the inside surface of the tubular member, which avoids creating stress concentrations in the tubular member when that portion is later expanded. Additionally, anchors utilizing resilient members are able to be constructed from a relatively few components, thus providing a less complicated and less expensive anchoring device.

Although this detailed description has shown and described illustrative embodiments of the invention, this description contemplates a wide range of modifications, changes, and substitutions. In some instances, one may employ some features of the present invention without a corresponding use of the other features. Accordingly, it is appropriate that readers should construe the appended claims broadly, and in a manner consistent with the scope of the invention. 

1. An apparatus for radially expanding and plastically deforming an expandable tubular member, comprising: an expansion device operable to radially expand and plastically deform the expandable tubular member as said expansion device is axially displaced relative to the expandable tubular member; an actuator coupled to said expansion device and operable to axially displace said expansion device relative to the expandable tubular member; and an anchor coupled to said actuator, wherein said anchor comprises a resilient member selectively deformable between a first position wherein said resilient member does not engage the expandable tubular member and a second position wherein said resilient member engages the expandable tubular member so as to releasably couple said anchor to the expandable tubular member.
 2. The apparatus of claim 1 wherein said resilient member is deformed from the first position to the second position by axially compressing said resilient member.
 3. The apparatus of claim 2 wherein said anchor further comprises a compression flange operable to axially compress said resilient member.
 4. The apparatus of claim 1 wherein said resilient member is deformed from the first position to the second position by radial expansion.
 5. The apparatus of claim 4 wherein said anchor further comprises a mandrel operable to radially expand said resilient member.
 6. The apparatus of claim 1 wherein said resilient member further comprises reinforcement members embedded therein.
 7. A method comprising: coupling an anchor comprising a resilient member to a first end of an actuator; coupling an expansion device to a second end of the actuator; disposing the anchor into an expandable tubular member; applying a force to the resilient member so as to deform the resilient member from a first position wherein the resilient member does not engage the expandable tubular member to a second position wherein the resilient member engages the expandable tubular member so as to releasably couple the anchor to the expandable tubular member; and radially expanding and plastically deforming the expandable tubular member by activating the actuator so as to axially displace the expansion device relative to the expandable tubular member.
 8. The method of claim 7, further comprising: removing the force from the resilient member so as to allow the resilient member to deform from the second position to the first position; axially displacing the anchor relative to the expansion device; applying a force to the resilient member so as to deform the resilient member from the first position to the second position; and radially expanding and plastically deforming the expandable tubular member by activating the actuator so as to axially displace the expansion device relative to the expandable tubular member.
 9. The method of claim 7, wherein the force applied to the resilient member is an axial compressive force.
 10. The method of claim 7, wherein the force applied to the resilient member is a radial expansion force.
 11. The method of claim 7, wherein the force applied to the resilient member is generated by a pressurized fluid.
 12. The method of claim 7, wherein deforming the resilient member to the second position does not plastically deform the expandable tubular member.
 13. The method of claim 7, wherein deforming the resilient member to the second position plastically deforms the expandable tubular member.
 14. A method comprising: coupling an anchor and an expansion device to an actuator to form an expansion assembly, wherein the anchor comprises a resilient member; disposing the expansion assembly at least partially within an expandable tubular member that is disposed within a wellbore; deforming the resilient member from a first position wherein the resilient member does not engage the expandable tubular member to a second position wherein the resilient member engages the expandable tubular member so as to releasably couple the anchor to the expandable tubular member; and radially expanding and plastically deforming the expandable tubular member by activating the actuator so as to axially displace the expansion device relative to the expandable tubular member.
 15. The method of claim 14, further comprising: returning the resilient member to the first position from the second position; axially displacing the anchor relative to the expansion device; deforming the resilient member from the first position to the second position; and radially expanding and plastically deforming the expandable tubular member by activating the actuator so as to axially displace the expansion device relative to the expandable tubular member.
 16. The method of claim 14, wherein the resilient member is deformed from the first position to the second position by applying a force to the resilient member and returns to the first position when the force is removed.
 17. The method of claim 16, wherein the force applied to the resilient member is an axial compressive force.
 18. The method of claim 16, wherein the force applied to the resilient member is a radial expansion force.
 19. The method of claim 14, wherein deforming the resilient member to the second position does not plastically deform the expandable tubular member.
 20. The method of claim 14, wherein deforming the resilient member to the second position plastically deforms the expandable tubular member. 